Sentinels of Disease: Engineering Bacteria to Sense and Remember Salmonella Infection in the Mammalian Gut

Enteric bacterial infections are a leading cause of global morbidity and mortality. Non-typhoidal Salmonella (NTS) species alone infect around 100 million people, and kill over 100 thousand of these, annually. Lack of accessibility to adequate medical care during severe infections is one of the major causes of death. The development of new, cheap and easy-to-administer diagnostics and therapeutics is therefore an important step towards better monitoring and treating this disease. We recently developed proof-of-concept engineered bacteria that sense the mammalian gut environment and remember its state for at least a week to be monitored by fecal sampling. Using ‘Gut-on-a-Chip’ microfluidic organ models and mouse models of Salmonella infection we have further developed this work to produce bacterial reporters that respond to markers of Salmonella infection in vitro and in vivo. This approach could provide a cheap and easy means to monitor infection and provides an important basis for the ongoing development of inducible therapeutics and other non-invasive diagnostic approaches using engineered bacteria.